Sunday, November 11, 2012

Another alarm again, from CalSky service. This time ISS would have passed in front of Sun disk at Espoo / Finland, on 10th November 2012. Estimated time was approximately 12:33. I tried to follow, also this time - plans were not successful. Sky was full cloudy...

Monday, November 5, 2012

Some background investigation is done now. Few samples from couple of DC/DC converter manufacturers, seems a good solution. One that I first noticed, was 75Watt series from Meanwell. Type MHB75-12S12 provides conversion from 4S LiPo cell voltage to constant output voltage. Most important spec are:

Friday, November 2, 2012

Another image from trip to Utö... This time one planetary nebula (Messier 27), as wide angle image. It is visible in image upper left corner, as green dot. Difficult imaging indeed, conditions were windy and I had to struggle keeping my tripod on the ground. Image taken with Nikon D200, Nikkor AF-S G 50mm, at f/1.4, single 8s exposure at ISO2500. Unfortunately sensor produces lot of noise :-(

This battery project, requires some additional electronics. Main purpose is to keep output voltage stable as the input voltage changes (depending on the amount of 4S LiPo cell discharge level).

There is many options and manufactures to look at... First I will check what local stores (like YE, Partco and Elfa) are selling. I will make later decisions, what voltage converter to use. Because of efficiency requirements, converter module based on the linear technology, is not an option here...

Thursday, November 1, 2012

My company photography club made a trip to Finland archipelago / Utö, at October 2012. There I got captured few images, related to optical phenomenon. Origin of seawater bow is same as in normal rainbow, light is reflected inside of seawater droplet.

Sunday, October 28, 2012

Project test continues with 4S LiPo battery (Orion 14.8V 6400mAh). Only D200 camera was powered. I used four diodes as voltage dropper (1N3879 switching diode). This solution is only temporary, more sophisticated one would be low loss switch mode voltage converter....

Results (27th Oct)*******************************Diodes heat up a bit during testing, without heat sink used. Test was stopped, when voltage per cell approx at 3.5V level (some cells were 3.2/3.3V, two last at 3.6V, slightly uneven discharging). Totally 472 images were taken. It corresponds to three times more images, than in 3S LiPo 2100mAh test setup.

Tuesday, October 23, 2012

I put the Orion 3S 11.1V LiPo cell (2100mAh version) to test. Nikon D200 is directly fed with this battery, no EN-EL3E used at battery slot. Small fuse of 2.5A is used in series to protect camera... I made the test without MB-D200 battery pack.

Power cord I took from my Nikon EH-6 AC supply. A sacrifice to science was made, and wire cut with scissors :-) Starting voltage at 3S LiPo battery, was 12.4V. I will at least run test down to 11.1V, maybe even a bit below that, if D200 still operates correctly.

Results (23rd October)
*******************************
Sequnce was run, until voltage under load was 3.5V per cell (overall 10.5V). Totally 145 images were taken. There is capacity increase noticed, when compared to 48 images with single EN-EL3E and 91 images with dual EN-EL3E (with MB-D200 battery grip).

Results (24th October)
*******************************
Orion 3S Lipo battery was charged again. Now it took bit longer than last time, approximately 75min to full charge. Test settings were same as above,
totally 149 images taken.

Sunday, October 21, 2012

Both batteries are now charged, all went OK as expected. No heating was noticed in the battery, when touched by hand. During 4S LiPo charging, charger itself heated (not still too hot to touch).

Following figures below, show the main data during charging. 3S LiPo was charged with full current (2.1A). Even it was defined higher current - 5 Amps - for the Orion 4S 6400mAh LiPo, approximate value was 3.3Amp.

Drawback in the first battery, is the output voltage range. In full charge (3*4.2V=12.6V) it can feed Nikon D200 without any voltage converter. When battery is discharged, voltage drops below the specified level. It remains to be seen, whether it affects to camera operation.... This battery equals to capacity, usually found in pro-DSLR's, like D3/D4.

The second one, provides approcimately three times capacity than first one (3S 2100mAh version). Output voltage in the 4S version, is too high to be connected directly to D200. Fully charged battery provides approximately 16.8V. Nikon own power supply EH-6 provides specified 13.5V output voltage. Connecting battery directly, might blow up my camera, and I do not want it to happen. So in first phase of test, I propably will make diode connection is series. That will drop voltage approximately 3V (5*0.6V). Then output voltage would vary somewhere in range of 11.8...13.8V.

Time to take a new project. Many times I have noticed on the outside, that Nikon D200 pulls out effectively the full charge out of batteries. The supplied EN-EL3E is not provided with a big capacity. In cold temperatures like -20...-30C, image count could be as less as 20...30.

Insteadt of using older lead-acid technology, I selected Litium technology. This provides higher capacity in same volume & weight. The downside of this, is higher price tag.

Purpose of this project, is to provide capacity at least 3 times, compared to normal setup with Nikon D200 drived with single or two EN-EL3E LiIon batteries. I selected LiPo (litium polymer) battery type, because those are easily available in stores selling stuff for RC hobbyists. Microcontrolled chargers, provide accurate charging of LiPo battery. More will follow, when project continues. Stay tuned :-)

Sunday, April 1, 2012

Few times, during last months there is display color problem. Display is not physically broken. It displays colors properly - when no requirement for accurate color reproduring, like image processing.

When problem appears, some colors in the normal palette are displayed wrongly. Usually hues of green are totally lost. And bright blueish and shades of grey - have strange color cast. Same applies with skin tones, those are looking like pink shades. Restarting of the laptop, solves problem.

The problem could be (?) related to the Intel display adapter /video drivers. I updated drivers, and the usage of laptop will tell - does it help to cure the problem.

Tuesday, March 27, 2012

Unfortunately, again problems with my Nikon D200 body. This time it is visible in the the raw -images already.

There was noticed strange banding all over the image area. Narrow stripes are located closely to each other. In a portrait image, stripes are visible as horizontally. The phenomenon gets worse, when the camera is exposed to low temperatures, like -20C and below that. I am not sure, is this a typical behavior for D200.

Two images attached, lower one is scaled from original to 800pix in height. Banding is only slightly visible. Upper image is direct crop in the middle of image, without scaling.

Wednesday, March 21, 2012

Little bit over one month ago, I had a trip to Pallas / Yllästunturi national park at northern Finland. We were snowshoeing there, with few colleagues from my company's photography club. These was cold and fresh winter air available, here's two halo images as sample:

Monday, March 19, 2012

Yesterday I got another alarm from CalSky -service, this time also ISS crossing the Moon disk. It happened at 19th March 2012, little bit before 8am - in Finnish local time. Not even a chance to observe, sleet was falling from the sky. Waiting for the next passing then...

Sunday, March 18, 2012

Approximately one week ago, I got email alert from the CalSky service. It predicted that the ISS would pass across the Moon disk at southern Finland, on Sunday morning 18th March 2012. The time for the crossing was 07:13:02 local time, re-checked yesterday - schedule was 07:12:57.

I tried to prepare equiment for taking image sequence of the ISS, with Nikon D200 and C8 OTA. Also found out that memory buffer at D200, fills is pretty quickly - max 5s sequence at 6fps. It would have needed at least 10...15s of buffer, because the passing of ISS would propably (?) change some seconds of the predicted time.

Another problem would been carrying the C8 scope to suitable place, since I do not have a car. On top of the building - there would be high place, but metal fence blocks the visibility. So then, waiting for the next passing of the ISS over moon or sun disk...

About Me

I'm 36 years old, currently living in southern Finland. One of my hobbies is nature photography. I got my SLR about eight years ago, nowadays I am mainly using digital SLR.
To areas in nature photography have been especially interesting to me, atmospheric phenomenons and nightsky. With this blog I share my experiences, interests and thoughts. Feel free to browse around!